/Engine/Source/Runtime/SlateCore/Public/Widgets/DeclarativeSyntaxSupport.h
template<typename Arg0Type, typename Arg1Type, typename Arg2Type, typename Arg3Type> struct T4RequiredArgs
Arg0Type &
Arg0
Arg1Type &
Arg1
Arg2Type &
Arg2
Arg3Type &
Arg3